Linkage Mapper

Linkage Mapper is a GIS tool designed to support regional wildlife habitat connectivity analyses. It consists of several Python scripts, packaged as an ArcGIS toolbox, that automate mapping of wildlife habitat corridors. We developed Linkage Mapper for the Washington Wildlife Habitat Connectivity Working Group’s (WHCWG) 2010 statewide connectivity analysis, and are making them public for use in other wildlife connectivity assessments.

Linkage Mapper uses GIS maps of core habitat areas and resistances to identify and map linkages between core areas. Each cell in a resistance map is attributed with a value reflecting the energetic cost, difficulty, or mortality risk of moving across that cell. Resistance values are typically determined by cell characteristics, such as land cover or housing density, combined with species-specific landscape resistance models. As animals move away from specific core areas, cost-weighted distance analyses produce maps of total movement resistance accumulated.

The tool identifies adjacent (neighboring) core areas and create maps of least-cost corridors between them. It then mosaics the individual corridors to create a single composite corridor map. The result shows the relative value of each grid cell in providing connectivity between core areas, allowing users to identify which routes encounter more or fewer features that facilitate or impede movement between core areas. Linkage Mapper also produces vector layers that can be queried for corridor statistics.

The code is optimized for ArcGIS 10.0, but is also tested for ArcGIS 9.3, 10.1, and 10.2.

New modules (Arc 10 only):

  • Barrier Mapper implements a new method for detecting important barriers to facilitate restoration planning (details on the method can be found in a new manuscript).
  • Pinchpoint Mapper uses Circuitscape to identify pinch-points (a.k.a. bottlenecks or choke points) in corridors produced by Linkage Mapper.
  • Centrality Mapper analyzes core and corridor centrality in networks produced by Linkage Mapper. This can help prioritize important corridors.
  • Climate Linkage Mapper rounds out the toolbox with the addition of a tool that maps corridors following climatic gradients to facilitate species range shifts under climate change. More details can be found in Nuñez et al. (2013) and on the Washington Wildlife Habitat Connectivity Working Group website.

Need to create resistance or core area layers? Check out Gnarly Landscape Utilities.

Please note: whatever tool you use, connectivity modeling involves a great deal of research, data compilation, GIS analyses, and careful interpretation of results. Defining areas to connect, parameterizing resistance models, and other modeling decisions you will need to make are not trivial. Before diving in, we strongly recommend that users first acquaint themselves with the process and challenges of connectivity modeling by consulting published resources. Good places to start include an overview of habitat and corridor modeling on the Corridor Designer website, the step-by-step guidance on connectivity assessments on the Connecting Landscapes website, and references listed in the Linkage Mapper user guide.

Linkage Mapper was developed with support from the Great Northern Landscape Conservation Cooperative and the Wildlife Conservation Society's Wildlife Action Opportunities Fund. The new modules listed above were supported by a grant from the North Pacific Landscape Conservation Cooperative.

Linkage Mapper is in active development. Please join the Linkage Mapper User Group for updates on new releases.